Fluid pressure tool



Feb. 21, 1933. G. M. NELL FLUID PRESSURE TOOL Filed April 6, 1929 2 Sheets-Sheet N I N A TTORNE Y.

Feb. 21, 1933. G. M. NELL FLUID PRESSURE TOOL Filed April 6, 1929 2 Sheets-Sheet 2 m QM Q INVENTOR. Gusfave M /Ve// A TTORNE Y.

Patented Feb. 21, 1933 UNITED STATES PATENT OFFICE GUSTAVE IvI. NELL, 013' DETROIT, MICHIGAN, ASSIGNOR TO CHICAGO PNEUMATIC TOOL COIKPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY FLUID PRESSURE TOOL Application filed. April 6, 1929.

This invention relates to percussive motors of the fluid pressure type such as are used in pneumatic hammers and rock drills. More particulariy it relates to the distribution and control of motive fluid by an automatically thrown valve and to certain structural fea tures of such motors.

Among the objects of the invention are to provide a compact form of motor in which external projections are avoided, to make the valve parts of simple construction and readily accessible for repair or replacement, to

provide a valve control arrangement which shall insure a full stroke of the hammer piston particularly on the power stroke, to incorporate the valve structure into the cylinder closing means of the percussive machine, and in general to improve prior machines and devices in the interest of more eiiicient and satisfactory service.

In order to illustrate the invention one concrete embodiment thereof is shown in the accompanying drawings, in which:

Fig. 1 is a longitudinal sectional view of a percussive drill;

Fig. 2 is a detailed sectional view on an enlarged scale substantially on the line 2-2 of Figs. 3 and a showing the valve case and valve lid with the valve in a different position from that shown in Fig. 1;

Figs. 3 and 4 are respectively left and right hand elevational or plan views of the assembly shown in Fig. 2.

Fig. 5 is an enlarged sectional view of the drill shown in Fig. 1 with a modified form of valve; and

Fig. 6 is an end elevational view of the valve shown in Fig. 5.

In the embodiment of the invention chosen for the purpose of illustration the cylinder 5 of the percussive drill has an atmospheric exhaust port 6 intermediate its length arranged to be overrun and controlled by the hammer piston 7 which is reciprocated within the piston chamber of the cylinder to impart blows to a suitable working tool, such as a drill steel 8, either directly or through an anvil block 9. Drill steel 8 is supported in a suitable manner in a chuck of any known or desired type by which rotation imparted to Serial No. 353,207.

piston 7 may be transmitted thereto. Since the chuck and the details of the front end construction of the drill form no part of the present invention, further description is omitted.

The rearward end of cylinder 5 is counterbored to receive and to support in line with the piston chamber a valve assembly which comprises valve case 10, valve lid 11, sleeve valve 12, and cylinder ring 13 These valve parts are all annular in shape, as indicated, and cylinder ring 13 has an extension 13a which projects through the bore of lid 11 and case 10 and telescopingly engages an internal flange 1060 on the latter (Figs. 1 and 2). Cylinder ring 13 is in turn engaged by a ratchet ring l l, which is also inserted within the counterbore of cylinder 5, and supports the head of a rifle bar 15, the bar portion of which extends through the bore of cylinder ring 13 and its extension 13a and is journaled in the same. The outer end of the counterbore is closed by a back head 16 secured to the drill cylinder in any suitable manner to retain the parts within the counter bore in assembled relation.

Motive fluid for operating the drill may be admitted through an inlet 16a in back head 16 from which ports lead to an annular groove 16b adjacent ratchet ring 14 through which a series of passages 17 extend and are continued through cylinder ring 13 and lid 11 to open into a live air chamber 17 on within a valve case 10. From the live air chamber 17a, but nearer the axis of the drill, a series of ports or passages 18 extend through valve case 10 directly into the rear end of the piston chamber. Opposite thereto, in lid 11, are a series of ports or passages 19 which make a right angular turn then extend radially through the lid into the cylinder wall where they make another right angular turn and extend parallel to the axis of the drill to open into the front end of the piston chamber.

The controlling valve 12 Figs. 14: is of the sleeve type and takes the form of a wheel when seen in side elevation since it comprises a hub portion 12a from which extends radially an annular flange portion 12b of substantial extent and uniform thickness. The exterior of hub portion 12a engages theinterior bore of both case 10 and lid 11 with a sliding fit, but the interior of the hub is spaced from cylinder ring extension 13a, as indicated in Fig. 1, to provide a chamber for a purpose presently to be described. The valve chamber into which flange portion 12?) extends is not much wider than the valve flange itself with the result that the valve has only a. slight movement between its two extreme positions. The opposite faces of flange 127) control the passing of motive fluid fr m live air chamber 17a to ports 18 and 19 respectively. Since valve flange 121) has only a slight clearance in relation to its peripheral retaining wall the capacity of live air chamber 170. is increased by cutting a concave or semicircular groove 120 in the outer peripheral surface of flange 12b.

Referring now to the central chamber or space between hub 12a of the valve and ring extension 13a, ports and passages are pro vided under control of valve 12 to utilize this space to provide an auxiliary exhaust for the piston chamber in either or both directions of the piston movement. Said space is made into an exhaust chamber by connecting it directly to atmosphere through one or more passages 20 (Fig. 1). Such passages may extend directly to atmosphere if desired or to the main exhaust groove 6, as shown, but in no case are they to be controlled either by piston 7 or by valve 12 but remain open at all times. Valve case 10 is provided with an annular groove 21 in position to be covered by valve hub 12a when the latter is in its forward position (Fig. 1) and to be uncovered or opened when the valve is in its rearward position (Fig. 2). A passage 21a leads from this groove outwardly to the cylinder wall and thence axially of the drill to open into the piston chamber at a point intermediate main exhaust port 6 and the front end of the piston chamber. A similar groove 22 in lid 11 similarly disposed for control by the opposite end of valve hub 12a communicates by passage 22a with the piston chamber at a point intermediate main exhaust 6 and the rearward end of toe piston chamber.

To insure the maintenance of all the parts mounted in the counterbore of cylinder 5, so that the ports and passages controlling the portion of the piston may be maintained in register, dowel pins 23 are provided which extend through suitable bores in lid 11, cylinder ring 13, and ratchet ring 14, and have their ends received in suitable sockets in back head 16 and valve case 10, as indicated in Fig. 1.

The operation of the motor is briefly as follows. lVith the parts in the positions shown in Fig. 1, piston 7 is moving rearwardly under motive fluid admitted through ports 19, while the rearward end of the piston chamber is open to exhaust through main exhaust port 6 as well as through the supplementary exhaust provided by passage 22a, groove 22, the exhaust chamber within valve 12, and the vent ports 20. When main exhaust 6 is closed by piston 7, the air trapped by the piston in the rearward end of the piston chamber continues to escape through the auxiliary exhaust until the cylinder port or ports leading to the same are covered by the piston. Then the compression of the trapped air, which has access to the flange 12E) of the valve throu h ports 18, builds up until the opening of the main exhaust 6 to the front end of the piston chamber by piston 7 produces a reduction of pressure on the other face of the valve flange with the result that the valve moves to the position shown in Fig. 2. Live air then passes from chamber 17a through ports 18 to the rearward end of the piston chamber to drive the piston forwardly. When the piston closes main exhaust 6, the air trapped in advance of the piston continues to escape through the auxiliary exhaust comprising the passage 21a, groove 21, the exhaust chamber within the valve, and vent passages 20 until piston 7 closes the cylinder ports leading to passages 21a whereupon pressure builds up through passages 19 against the rearward face of valve flange 12?) resulting in the throwing of the valve back to its forward position shown in Fig. 1 when the main exhaust 6 is uncovered.

In Figs. 5 and 6 a modified form of valve is disclosed but the operation and functioning of the same is substantially that of the valve disclosed in Figs. 14: inclusive. The modified valve 112 comprises a hub portion 112a with a radially extending annular flange portion 1125 having an annular outwardly directed recess 1120 of somewhat eater depth and different shape than that provided for valve 12. Each face of flange 1127) has a central portion controlling ports 18 and 19 with reduced portions on either side thereof to provide balancing areas for the valve. These reduced portions are provided by the inner annular grooves 112d and outer annular grooves 1126. The outer grooves 112@ communicate with the live air chamber 17a while the inner grooves 112d are continuously supplied with motive fluid in limited amount from annular chamber 1120 by ports 112 The annular balancing areas provided by grooves 112d and 1126 permit easy access of live air to portions of the opposed valve faces to assist compression in throwing the valve' If desired, the control portions of the valve faces for ports 18 and 19 may have annular grooves 1129 with restricted ports 11% communicating therewith to allow a limited amount of live air or motive fluid to pass from the live air chamber 1120 to the piston chamber to give more fluid for compression by the piston when found necessary or to aid the motor in starting. These slight changes in the valve have a tendency to speed up and otherwise to improve the valve action but do not materially change the control or functioning from that set forth above in relation to the form of the valve shown in Figs. 1-4.

From the above it will be apparent that the present invention provides a single and compact valve arrangement in which the valve is thrown automatically by air compressed by the piston with the additional advantage of an auxiliary valve controlled exhaust for either or both ends of the piston chamber whereby any tendency on the part of the piston to short stroke or find a dead center is-avoided.

WVhile the invention has been herein shown in what is now considered to be a preferred form with minor variations in the valve itself, it is to be understood that the invention covers all changes, modifications, and adaptations within the scope of the appended claims. 7

I claim as my invention:

1. In a fluid pressure motor, a cylinder havin an exhaust ort intermediate its is P length, a piston reciprocable in said cylinder and controlling said port, a valve chest providing an annular valve chamber and ports leading to opposite ends of the piston chamand controlling said port, a valve chest in linewith the piston chamber and at one end thereof, said chest providing an annular valve chamber, and having ports leading to the opposite ends of the piston chamber, a sleeve valve having a flange providing opposed faces for controlling the ports in said valve chest, and auxiliary exhaust means for said piston chamber controlled by said valve including an atmospheric exhaust chamber Within said valve.

3. In a fluid pressure motor, a cylinder having an exhaust port intermediate; its length, a piston reciprocable in said cylinder and controlling said port, rotative mechanism including a rifle bar extending axially into said cylinder and having cooperating engagement with said piston, an annular valve chest in line with said cylinder and having ports extending to the opposite ends of said piston chamber, said chest having an internal flange, a cylinder ring in face engagement with said chest and having an annular extension projecting within the latter and telescopingly engaging said flange, said ring providing an extended bearing for said rifle bar, a sleeve valve in said chest slidably engaging the latter and having an annular flange for controlling said ports, said valve being spaced from said ring extension to provide an exhaust chamber in communication with atmosphere, and means utilizing said exhaust chamber and under control of said valve for providing an auxiliary exhaust for at least one end of said piston chamber.

4. In a fluid pressure motor, a cylinder having an exhaust port intermediate its length, a piston reciprocable in said cylinder and controlling said port, rotative mechanism including a rifle bar extending axially into said cylinder and having cooperating engagement with said piston, an annular valve chest in line with said cylinder and having ports extending to the opposite ends of said piston chamber, said chest having an internal flange, a cylinder ring in face engagement with said chest and having an annular extension projecting within the latter and telescopingly engaging said flange, said ring providing an extended bearing for said rifle bar, a sleeve valve in said chest slidably engaging the latter and having an annular flange for controlling said ports, said valve being spaced from said ring extension to provide an exhaust chamber in communication with atmosphere, said cylinder having ports on opposite sides of said exhaust port intermediate the latter and the ends of the piston chamber, and passages extending from said last named ports to said exhaust chamber under control of the hub portion of said valve for providing an auxiliary exhaust to insure a full stroke of the piston in both directions.

5. A valve assembly for insertion into the end of the cylinder of a fluid pressure drill comprising a valve case, a valve lid, said case and lid having a bore therethrough, a cylinder ring engaging one of said parts and having an extension projecting through the bore of both, said case and lid and ring providing an annular valve chamber, and a sleeve valve in said chamber having a hub portion slidably engaging said case and lid but wholly out of contact with said ring and said extension to provide an internal exhaust chamber, said case and lid having ports controlled by the hub portion of said valve and alternately put in communication with said exhaust chamber.

6. A valve assembly for insertion into the end of the cylinder of a fluid pressure drill comprising a valve case, a valve lid, said case and lid having a bore therethrough, and an internally projecting flange on said case, a cylinder ring engaging said lid and having an annular extension projecting through said lid and into telescoping engagement with said internal flange on said case, said case, lid, and ring providing an annular valve chamber, a sleeve valve comprising a hub and a flange extending between said case and lid to control the ports therein, said hub portion slidably engaging said case and lid but .being in spaced relation to said ring extension to provide an exhaust chamber within the bore of said sleeve valve and entirely apart from the chamber in which said valve flange is disposed, and means under control of said valve for utilizing said exhaust chamber in the operation of the drill.

7. In a fluid pressure motor, a cylinder providing a piston chamber, a piston reciprocable therein, a valve chest providing an annular valve chamber and ports leading to opposite ends of said piston chamber, a valve provided with a flange having oppositely directed faces for controlling said ports, said faces being arranged to provide balancing areas enclosing the port controlling portions of said faces, and means for passing motive fluid continuously to said balancing areas in limited amount.

8. In a fluid pressure motor, a cylinder providing a piston chamber, a piston reciprocahle therein, a valve chest providing an annular valve chamber and ports leading to opposite ends of said piston chamber, a sleeve valve provided with a flange having oppositely directed portions for controlling said ports and annular grooves on both sides of said portions to provide balancing areas, and means for passing motive fluid continuously in limited amount to said balancing areas.

9. In a fluid pressure motor, a cylinder providing a piston chamber, a piston reciprocable therein, a valve chest providing an annular valve chamber and an annular series of ports at each end of said chamber leading to the opposite ends of said piston chamber, a valve having oppositely directed faces for controlling said ports, said valve having a groove on one of its faces in position to register with the ports to be controlled thereby and means supplying motive fluid in limited amount continuously to said groove.

10. In a fluid pressure motor, a cylinder providing a piston chamber, a piston reciprocable therein, a valve chest providing an annular valve chamber and an annular series of ports at each end of said chamber leading to the opposite ends of said piston chamber, a valve having oppositely directed faces for controlling said ports, said valve having a groove on one of its faces in position to register with the ports to be controlled thereby, and means supplying motive fluid in limited amount continuously to said groove, said valve having an annular reduced portion spaced inwardly from said groove to provide a balancing area.

11. In a fluid pressure motor, a cylinder providing a piston chamber,'a piston reciprocable therein, a valve chest providing an annular valve chamber and an annular series of ports at each end of said chamber leading to the opposite ends of said piston chamber, a valve having oppositely directed faces for controlling said ports, said valve having a groove in one of its faces in position to register with the ports to be controlled thereby, and means supplying motive fluid in limited amount continuously to said groove, said valve having annular reduced portions on either side of said groove and in spaced relation .to the same to provide balancing areas.

12. In a fluid pressure motor, a cylinder providing a piston chamber, a piston reciprocable therein, a valve chest providing an annular valve chamber and an annular series of ports at each end of said chamber leading to the opposite ends of said piston chamber, a valve having oppositely directed faces for controlling said ports, said valve having concentric grooves on its faces, one of the grooves on each said face being in position to register with the ports controlled thereby and the other groove to provide a balancing area, and means directing motive fluid in limited amountto all of said grooves.

13. In a fluid pressure motor, a cylinder providing a piston chamber, a piston reciprocable therein, a valve chest providing an annular valve chamber and an annular series of ports at each end of said chamber leading tothe opposite ends of said piston chamber, a valve having oppositely directed faces for controlling said ports, said valve having concentric grooves in its faces, one of the grooves on each said face being in position to register with the ports controlled thereby and the other groove to provide a balancing area, and means including ports in said valve for directing motive fluid in limited amount to all of said grooves.

14. A valve for fluid pressure motors, said valve being of the sleeve type and comprising a hub and a flange of substantial width eX tending radially therefrom and having a deep groove in the peripheral portion thereof, said flange having an annular groove in one end face thereof and a port for establishing communication between said grooves.

15. A valve for fluid pressure motors, said valve being of the sleeve type and comprising a hub and a single flange of substantial Width extending radially therefrom and having a deep groove in the peripheral portion thereof, said flange having spaced annular grooves in one end face thereof and ports establishing connection between said face grooves and said peripheral groove.

16. A valve for fluid pressure motors, said valve being of the sleeve type and comprising a hub, and a single flange of substantial width extending radially therefrom and having a deep groove in the peripheral portion thereof, said flange having concentric annular grooves on the oppositely directed end faces thereof and ports in said flange for establishing communication between certain of said annular grooves and said peripheral groove.

17. In a fluid pressure motor, a cylinder having an exhaust port intermediate its length, a piston reciprocable in said cylinder and controlling said exhaust port, a valve chest having a. circular chamber of relatively small diameter and another circular chamber of relatively large diameter, a valve having a hub portion Within said small diameter valve chest chamber and an enlarged flanged portion Within said large diameter valve chest chamber, said enlarged flanged portion controlling admission of motive fluid to the ends of said cylinder, and said hub portion arranged to open and close an auxiliary exhaust conduit from one end of said cylinder.

Signed. by me at Detroit, in the county of Wayne and State of Michigan, this 2nd day of April, 1929.

' GUSTAVE M. NELL. 

